Die cutting press with control means for varying the up stroke



Sept 8, 165 M. SALWAY-WALLER 3,208,324

DIE CUTTING PRESS WITH CONTROL MEANS FOR VARYING THE UP STROKE FiledSept 18, 1963 2 Sheets-Sheet l Inventor Malcolm SaZway-[Valler B hzsAttarne DIE CUTTING PRESS WITH CONTROL MEANS FOR VARYING THE UP STROKEFiled Sept. 18, 1963 Sept. 28, 1965 M. SALWAY-WALLER 2 Sheets-Sheet 2 NEF E H I NQN/ J m o N 3 #8 $0: T H W1 W E K H N3 .3 Q J W L B g 33% T 3 gb T 5 Sb mfiiw wk 3% 3% Q 1% m Xx N&\ w T w NQ w) m\ E W A .1 a: *5

United States Patent O 3,208,324 DIE CUTTING PRESS WITH CONTROL MEANSFOR VARYENG THE UP STROKE Malcolm Salway-Waller, Leicester, England,assignor to United Shoe Machinery Corporation, Boston, Mass, acorporation of New Jersey Filed Sept. 18, 1963, Ser. No. 309,779 Claimspriority, application Great Britain, Oct. 2, 1962, 37,261/62 5 Claims.(Cl. 83-527) This invention relates to improvements in die cuttingpresses and more particularly to improvements in control means forhydraulically operated die cutting presses for governing the cuttingstroke thereof, that is, the movement of the presser member toward andaway from the cutting bed in pressing freely movable dies through workpieces thereon.

This invention is illustrated as embodied in a hydraulic die cuttingpress of the type commonly known to shoe manufacturers as a clicker inwhich the presser member is a beam swingably supported on one uprightpost beside the cutting bed. However, the invention is not limited touse in the illustrative machine nor to presses having the presser membermounted on a single post.

The organization of present hydraulic die cutting presses with which thepresent invention is concerned comprises a frame supporting a cuttingbed, a presser member supported on the frame for movement toward andaway from the bed, power means for effecting movement of the pressermember, manual means for causing the power means to effect movement ofthe presser member to move it into pressing engagement with a die on awork piece supported on the cutting bed to press the die through thework piece and stroke terminating means responsive to the occurrence ofa predetermined event to cause the power means to effect movement of thepresser member away from the bed to return it to a rest position spacedfrom the cutting bed. The power means employed in such presses comprisesa cylinder and piston motor connected between the frame and the pressermember, generally'through a post or beam spindle on the return portionof the press stroke, the motor has been operated to drive the piston toits maximum limit of travel while adjustments of the rest position ofthe presser member have been provided through means for varying themechanical connection of the presser member to the motor such as thewell known hand-wheel operating on a threaded connection between thepost and the motor.

For maximum productivity, this rest position desirably is that at whichthe presser member will just clear a die resting on the work supportedon the cutting bed. Accordingly changes in die height or work thickness,or both, may change the desirable setting of the rest position.

Adjustment of the rest position by hand-wheel operation of threadedconnections has proved so arduous for the operator that several attemptshave been made to relieve the eifort required. Generally, however, theproposed means, such as reversible power means for operating thehand-wheel, have also incorporated considerable complexity and expenseinto the machine. Further, such power operated adjustment means takeeffect while the machine is running but not in stroke motion so that thepresser member undergoes at that time movement in accordance with theadjustment which, particularly in the case of downward adjustment, maycreate a hazard to an operators hand.

Accordingly, it is an object of the present invention to provide simpleand economical means for manually adjusting the rest position of thepresser member which means will be easy to manipulate.

3,298,324 Patented Sept. 28, 11965 ice Another object of the inventionis to provide in a die cutting press means for readily adjusting therest position of the presser member which means will take effect onlyduring the stroke cycle of the press.

To these ends and in accordance with a feature of the present invention,a die cutting press having a cutting bed, a presser member mounted formovement toward and away from the cutting bed, power means for effectingmovement of the presser member and control means comprising manual meansfor causing the power means to effect movement of the presser membertoward the cutting bed and stroke terminating means for causing thepower means to terminate such movement and to effect movement of thepresser member away from the bed is provided with manually adjustabletime delay means for causing the power means to cease effecting movementof the presser member way from the bed a predetermined time intervalafter initiation of such movement.

Thus the rest position is determined by the length of the time interval,adjustment of which, suitably and as illustrated, is effected by varyinga manually adjustable resistance element, does not take effect until thenext ensuing stroke.

Further features and advantages of the invention will best be understoodfrom the following description taken together with the accompanyingdrawings in which:

FIG. 1 is a schematic representation of the essential portions of apress embodying the invention; and

FIG. 2 is a circuit diagram of the control means for the illustrativepress.

The illustrative press is a press for effecting cutting operations onsheet material such as leather, metal, paper or fabrics and comprises aframe 8 (only a portion of which is shown in FIG. 1) carrying a worksupporting bed 10 and a presser member including a beam 12 between whichthe sheet material 20 and a freely movable cutting die 14 may bepositioned. The beam 12 is fixedly secured to an upper end portion of apost 18 journalled in alignd bearings in the frame so that the beam maybe swung about an upwardly extending axis at one side (e.g., the rear)of the bed so as to enable a portion of the beam to be brought oppositeto a selected portion of the bed.

Power means comprising a fluid pressure operated motor is provided inthe illustrative press for effecting movement of the beam towards andaway from the bed and thereby to bring about relative movement ofapproach between the bed and the beam to cause penetration of the sheetmaterial by a cutting edge of the cutting die so as to effect a cuttingoperation on the sheet material (e.g., to form a blank therefrom), and,subsequent- 1y, relative movement of separation between the bed and thebeam.

For this purpose there is provided a cylinder 22 (coaxial with the post18) in which is slidably mounted a piston 24 rigidly secured to a lowerend portion of the post 18. Ports 26 and 28 respectively communicatingwith upper and lower end portions of the cylinder (above and below thepiston 24) are connected with a double solenoid valve V schematicallyrepresented in FIG. 1 of the drawings. Fluid is supplied to the valve V,from a sump S, by a pump P, and fluid may be returned from the valve tothe sump via a pipeline 30.

The operative elements of the valve V are under the control of twosolenoids SOL 1 and SOL 2.

The construction and arrangement of the valve V and the associated fluidpressure circuit are such that:

(1) when both solenoids SOL 1 and SOL 2 are de-energized the ports 26and 28 are in communication (via the valve V) but are isolated from thepump P and the sump S; oil circulates from the pump P to the sump S;

due to the fact that the upper and lower areas of the piston 24 aredifferent piston displacement involves a net volume change, and sincethis is prevented the fluid within the cylinder 22 holds the piston atwhatever level it occupied at the end of the previous operation of themachine;

(2) when both solenoids SOL 1 and SOL 2 are energized the port 26 is putin communication with the pump P while the port 28 is connected toexhaust via the pipeline 30; the beam thus descends under power at arate predetermined by the delivery rate of the pump and the upper areaof the piston 24 to effect a cutting operation on the sheet material;

(3) when SOL 2 is de-energized, SOL 1 remaining energized, the ports 26and 28 are connected together and fluid under pressure is supplied toboth; because of the larger under surface area of the piston the pistonrises (at a rate predetermined by said delivery rate and thedifferential area of the piston, flow of fluid taking place from aboveto below the piston) to raise the beam; on deenergizing SOL 1 movementof the beam ceases, the fluid pressure circuit now being in condition(1).

The solenoids SOL l and SOL 2 are included in an electric circuit whichis shown diagrammatically in FIG. 2.

An A.C. supply (e.g., at 110 v.) is supplied over lines 50, 52 whilerectifiers D1 and D2 provide in lines 54 and 56 respectively a DC.supply of the polarity indicated in FIG. 2, capacitors C1 and C2 actingas smoothing capacitors. The solenoids SOL 1 and SOL 2 are connected inbranch lines 58, 60 across the AC. supply lines and 52, the branch linesincluding the normally closed contacts RlA and RIB of a relay R1 and theline including (in series with SOL 2) normally closed contacts R2A of arelay R2.

The relay R1 is a two coil relay, one coil Rl-L of which is connected,through a line 62 to normally open contacts of a pair of seriesconnected stroke-initiating switches SW1 and SW2, normally closedcontacts A of which charge a capacitor C3 via a suitable resistor fromthe line 54. When both switches SW1 and SW2 are actuated by theoperator, contacts B are closed and the charge stored in the capacitorC3 is discharged, via the line 62, through the first coil R1L of relayR1, thus closing the contacts RlA and RlB and also hold-in contacts RICwhich connect a line 64 with the +D.C. line 54 thus energizing SOL 1 andSOL 2 to initiate a press stroke. The line 64 is connected, via asuitable resistor, with the second coil R1-R of the relay R1 and thusthis relay is maintained in an energized condition.

The line 64 is also connected to the anode circuits of a pair ofelectron discharge devices, 66, 68 of the thyratron type, the anodecircuit of thyratron 68 also including the operating the coil of therelay R. The thyratrons 66, 68 and their associated components togetherwith a pressure switch PS and bottom limit switch LS provide a stroketerminating control circuit operative responsively to the occurrence ofa predetermined event for causing the power means to cease effectingmovement of the beam toward the bed and for causing the power means toeffect return movement. This circuit is generally similar to thatdisclosed in United States Letters Patent No. 2,821,670 issued January28, 1958 on an application filed February 11, 1955, in the name ofRobert W. Bradley.

In the illustrative press now being described, as in the press disclosedin said patent, the beam and the bed comprise electrically conductiveportions disposed opposite one another, a conductive portion on the beambeing provided by a cutting plate 70 secured to, but insulated from, thebeam 16, and a conductive portion on the bed being provided by anelectrically conductive cutting pad 72 in intimate contact with themetallic bed which is grounded. The cutting plate '70 is connected via asuitable resistor '74 to the control grid of the thyratron 66 which isnormally biased negatively with respect to its cathode by a suitablebiasing circuit (including a transformer Tl, a rectifier D4, capacitorC4 and a resistor 76) as shown in the diagram, FIG. 2. The cathode isconnected to the bed of the machine. The press is adapted to be usedwith a cutting die which provides a further electrically conductiveportion which is arranged, on penetration of the sheet material by acutting edge portion of the cutting die, electrically to bridge the gapbetween the electrically conductive portions (provided by the plate 70on the beam and the cutting pad 72 on the bed) and thus to remove thebias from the thyratron 66 which thereupon fires producing a positivepotential at its cathode across a resistor '78. This potential ispassed, via an adjustable time delay T.D. (comprising a network ofresistors and capacitors) to the control grid of the thyratron 68. Thisthyratron is also normally held non-conducting since its cathode ismaintained at a suitable positive potential with respect to its grid byresistors 80, 82 across the positive D.C. supply. When, after a suitableshort time delay following the establishment of the circuit through thebeam, the die and the bed (to insure complete cutting through of thedie), the positive potential at the cathode of the thyratron 66 chargesthe capacitors of the time delay network sufiiciently to raise thepotential of the grid of thyratron 68 to cause it to fire, the relay R2is operated to open contacts R2A and deenergize solenoid SOL 2. Valve Vis thus operated to reverse the beam, the beam rising until solenoid SOL1 is de-energized.

Closure of the switches PS or LS shunting the tube 68 in responserespectively to the occurrence of overpressure or the arrival of thebeam during its movement toward the bed at a predetermined positionoperates directly to energize the relay R2.

The illustrative machine includes manually adjustable time delay meanswhich is triggered responsively to the occurrence of said predeterminedevent by an electric signal generated at the time that reversal of thebeam is initiated by the operation of relay R2 and which acts tode-energize relay R1, and hence to de-energize solenoid SOL 1 after adesired time delay interval. By adjustment of this interval during whichthe beam is rising, the final height of the beam above the bed will beadjusted.

- By adjustment of the time delay arrangement just referred to theoperator is enabled to adjust the height of the beam above the bed toaccommodate work pieces of different thicknesses.

The time delay means for adjusting the return stroke of the beamcomprises a pair of thyratrons 90, 92 connected in a circuit which isbasically similar to that incorporating the thyratrons 66, 68.

The anodes of the thyratrons 90, 92 are connected to a line 94 which isconnected to line 62. Both thyratrons are normally biased so as to benon-conductive, the grid circuit of thyratron including a source of biasvoltage (comprising a transformer T2, a rectifier D5, a capacitor C6 anda feed resistor 96). The thyratron 92 is normally held non-conductive byvirtue of the fact that its cathode is at a positive potential withrespect to its grid, the positive potential being provided by resistors98, 100' in series across the negative D.C. line.

When the thyratron 68 fires to initiate a return stroke of the beam apositive pulse (constituting an electric signal generated at the time ofbeam reversal) is passed via a capacitor C5 and a lead 102 to the gridof the thyratron 90 which fires producing a positive voltage across aresistor 104 in its cathode circuit. The cathode is connected via avariable resistor POT 1, suitably mounted on the beam or frame forconvenient manual adjustment, to a capacitor C7 shunted with a very highresistance the resistor and capacitor forming a variable time constantcircuit. When the cathode potential rises C7 is charged via POT 1, andafter a time interval, depending upon the setting of POT 1 the potentialacross C7 rises sufliciently to fire the thyratron 92 to the grid ofwhich the capacitor is connected via a feed resistor. When thratron 92fires, current is drawn through the coil Rl-L of relay R1 by boththyratrons 90, 92 providing equalized magnetic opposition to the coilRl-R to permit relay R1 to drop out, thus de-energizing both solenoidsSOL 1 and SOL 2 to arrest upward movement of the beam. Opening ofcontact RlC of relay R1 cuts off the anode supply to the variousthyratrons and also isolates the operating coil of R1 from line 54. Thecircuit is thus reset and the press is ready for the next cuttingoperation. The purpose of the diode D3 is to ensure that the thyratrons90 and 92, having fired, do not draw current from line 52 and remain ina conducting condition. The diode D6 ensures that capacitor C7discharges rapidly, after the thyratron 90 ceases to conduct, inpreparation for the next cutting operation.

If after the completion of a cutting operation the resistor POT 1 ismanually adjusted, no immediate change in the height of the beam occurs.The press has first to be tripped in the usual way. On the return strokethe beam moves upwardly to the newly selected position.

The press incorporates a safety feature (like that employed in the pressdescribed in said Patent No. 2,821,670) whereby, if during descent ofthe beam, the striking plate contacts one hand of the operator, whichhand is at a different potential from the plate, being at ground whilethe other hand is still grasping the controlling handle on the beam(whereby it is swung and positioned over the die by the operator), thethyratron 66 will fire initiating a return stroke of the beam. In thiscase the beam will rise to a position (above the point at which reversaloccurred) which depends on the setting of the resistor POT 1. Thisfeature may be used when it is desired to raise the beam to a levelabove that which it is occupying.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In a die cutting press having a frame, a work, supporting bed carriedby the frame, a presser member mounted on the frame for movement towardand away from the work supporting bed, power means operable to effectmovement of said presser member toward and away from said bed, incombination therewith, control means for said power means including:

manually actuatable means for causing said power means to effectmovement of the presser member toward the bed;

stroke terminating means responsive to the occurrence of a predeterminedevent for causing said power means to terminate the movement of thepresser member toward the bed and to effect movement of the pressermember away from the bed; and manually adjustable time delay means forcausing the power means to cease effecting movement of the pressermember away from the bed a predetermined time interval after initiationof such movement. 2. In a die cutting press having a frame, a worksupporting bed carried by the frame, a presser member mounted on theframe for movement toward and away from the work supporting bed, powermeans including a fluid pressure operated motor for moving the pressermember toward and away from said bed and means for supplying fluid underpressure to said motor, in combination therewith, control means having:

manually actuatable trip means for causing said power means to move thepresser member toward the bed;

stroke terminating means responsive to the occurrence of a predeterminedevent for causing the power means to effect movement of the pressermember away from the bed; and

manually adjustable time delay means controlled by said terminatingmeans for causing the power means to cease effecting movement of thepresser member 6 away from the bed upon the expiration of apredetermined time delay interval. 3. In a die cutting press having aframe, a work supporting bed carried by the frame, a presser membermounted on the frame for movement toward and away from the worksupporting bed, power means operable to effect movement of said pressermember toward and away from said bed, in combination therewith, controlmeans for said power means including:

manually actuatable means for causing said power means to effectmovement of the presser member toward the bed;

stroke terminating means responsive to the formation of an electric pathbetween opposed electrically conductive portions of the presser memberand bed for causing said power means to terminate the movement of thepresser member toward the bed and to effect movement of the pressermember away from the bed; and

manually adjustable time delay means arranged for initiation upon suchreversal of the movement of the presser member for causing the powermeans to cease effecting movement of the presser member away from thebed after a predetermined delay interval.

4. In a die cutting press having a frame, a work supporting bed carriedby the frame, a presser member mounted on the frame for movementtowardand away from the work supporting bed, power means operable toeffect movement of said presser member toward and away from said bed, incombination therewith, control means for said power means including:

manually actuatable means for causing said power means to effectmovement of the presser member toward the bed;

stroke terminating means responsive to the formation of a conductivepath between a cutting plate attached to said presser member and anobject at a different electric potential for causing: said power meansto terminate the movement of the presser member toward the bed and tomove the presser member away from the bed; and

variable time delay means controlled by said stroke terminating meansand arranged for initiation thereby upon such reversal of the movementof the presser member for causing the power means to cease effectingmovement of the presser member away from the bed after a predetermineddelay interval. 5. In a die cutting press having a frame, a worksupporting bed carried by the frame, a presser member mounted on theframe for movement toward and away from the work supporting bed, powermeans comprising a fluid operated motor operable to effect movement ofsaid presser member toward and away from said bed and means forsupplying fluid under pressure to said member, in combination therewith,control means for said power means including:

solenoid valve means connected between said supply means and said motorand operable in governing the supply of fluid thereto for causing saidpower means to effect movement of the presser member toward or away fromthe bed or to oppose movement of the presser member in either of saiddirections;

manually actuatable switch means connected with said valve means forcausing said power means to effect movement of the presser member towardthe bed;

stroke terminating means connected to said valve means and operative inresponse to the occurrence of a predetermined event for operating saidvalve means to cause said power means to cease effecting movement of thepresser member toward the bed and to effect movement of the member awayfrom the bed; and

time delay relay means initiated responsively to the oc 7 8 currence ofsaid predetermined event for operating manually adjustable resistanceelement controlling said valve means after a delay interval to cause thedelay interval.

said power means to oppose further movement of the presser member, saidrelay means including a resistance-capacitance time constant circuithaving a 5 ANDREW R. JUHASZ, Primary Examiner.

No references cited.

1. IN A DIE CUTTING PRESS HAVING A FRAME, A WORK SUPPORTING BED CARRIEDBY THE FRAME, A PRESSER MEMBER MOUNTED ON THE FRAME FOR MOVEMENT TOWARDAND AWAY FROM THE WORK SUPPORTING BED, POWER MEANS OPERABLE TO EFFECTMOVEMENT OF SAID PRESSER MEMBER TOWARD AND AWAY FROM SAID BED, INCOMBINATION THEREWITH, CONTROL MEANS FOR SAID POWER MEANS INCLUDING:MANUALLY ACTUATABLE MEANS FOR CAUSSING SAID POWER MEANS TO EFFECTMOVEMENT OF THE PRESSER MEMBER TOWARD THE BED; STROKE TERMINATING MEANSRESPONSIVE TO THE OCCURRENCE OF A PREDETERMINED EVENT FOR CAUSING SAIDPOWER MEANS TO TERMINATE THE MOVEMENT OF THE PRESSER